Fastening element and method for securing a support rail to a mounting base

ABSTRACT

A fastening element for fastening a support rail to a mounting base induces a block-type base member that is fastenable to the support rail and includes a through-hole. The fastening element also includes a connecting element disposed in the through hole of the base member. The connecting element is adapted to fasten the support rail to the mounting base and configured to extend through the support rail and the mounting base in a fastened state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase application under 35 U.S.C.§371 of International Application No. PCT/EP2012/004386, filed on Oct.19, 2012, and claims benefit to German Patent Application No. DE 10 2011054 725.8, filed on Oct. 21, 2011. The International Application waspublished in German on Apr. 25, 2013 as WO 2013/056849 A1 under PCTArticle 21 (2).

FIELD

The invention relates to a fastening element for fastening a supportrail to a mounting base. The invention further relates to a method forfastening a support rail to a mounting base.

BACKGROUND

Electrical components, such as for example terminal blocks, are used fordistributing electric power and electrical signals in the industrialsphere. They are mounted on a support rail within a switchgear. Thesupport rail in turn is fastened to a mounting base, such as for examplea mounting plate or a frame structure, which in turn is inserted into aswitchgear cabinet. When fastening the support rail to the mountingbase, it is important that the support rail have a secure mechanicalseat on the mounting base, so that mechanical environmental factors,such as vibrations or jarring, do not result in a change in the positionof the support rail and hence of the electrical components arranged onthe support rail.

The support rail is usually fastened to the mounting base by means of ascrew connection or rivet connection, with the screw or rivets usedtherefor being placed directly on the support rail in order to connectthe support rail to the mounting base via bores which are alreadyprovided in the support rail and in the mounting base. In such case, itis necessary for the fastening point at which the fastening of thesupport rail to the mounting base occurs to be freely accessible to atool. To this end, in the case of short support rails frequently adistance of approx. 20 mm from the first electrical components which areplaced on is left free at the two opposite ends of the support rail. Inthe case of longer support rails which require one or more furtherfastening points, corresponding free spaces likewise have to be providedbetween the electrical components which are placed on. Only thus can itbe ensured that the fastening point between the support rail andmounting base can be reached, as a result of which however the number ofelectrical components which can be mounted on the support rail isreduced. If no corresponding free space is to be provided, the supportrail can be equipped with the electrical components only once thesupport rail is already fastened to the mounting base.

SUMMARY

In an embodiment, the present invention provides a fastening element forfastening a support rail to a mounting base. The fastening elementincludes a block-type base member that is fastenable to the support railand includes a through-hole. The fastening element also includes aconnecting element disposed in the through hole of the base member. Theconnecting element is adapted to fasten the support rail to the mountingbase and configured to extend through the support rail and the mountingbase in a fastened state thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described in even greater detail belowbased on the exemplary figures. The invention is not limited to theexemplary embodiments. All features described and/or illustrated hereincan be used alone or combined in different combinations in embodimentsof the invention. The features and advantages of various embodiments ofthe present invention will become apparent by reading the followingdetailed description with reference to the attached drawings whichillustrate the following:

FIG. 1 is a diagrammatic view of a fastening element according to anembodiment of the invention,

FIG. 2 is a diagrammatic view of a cut-out of the fastening elementshown in FIG. 1 in the region of a mounting foot in a partial sectionalview,

FIG. 3 is a diagrammatic view of a fastening element according to anembodiment of the invention, and

FIG. 4 is a diagrammatic sectional view of the fastening element shownin FIG. 3.

DETAILED DESCRIPTION

An aspect of the present invention provides for the improvement of thehandling of support rails. In particular, an aspect of the inventionpermits the fastening of a support rail which is already equipped withelectrical components, without having to provide for this a certainnumber of free spaces on the support rail for fastening the support railto a mounting base.

In an embodiment, the present invention provides a fastening element forfastening a support rail to a mounting base which has a block-type basemember which can be fastened to the support rail, with a connectingelement being guided in a through-hole formed in the base member, viawhich connecting element the support rail can be fastened to themounting base, with the connecting element being guided through thesupport rail and the mounting base in a fastened state.

In an embodiment of the invention the fastening of the support rail to amounting base does not takes place directly via a screw connection orrivet connection, but instead uses a separate component in the form of afastening element which has a block-type base member which is providedwith a through-hole in which is guided a connecting element via whichthe support rail can be fastened to the mounting base, for example amounting plate or a frame structure. This fastening element, togetherwith the electrical components which are to be placed on the supportrail, is placed onto the support rail from above and is fastened to thesupport rail, for example by a clamping or latching connection, beforethe support rail is fastened to the mounting base. By placing thefastening element onto the support rail from above, the fasteningelement can be fastened to the support rail at any points whatsoeveralong the longitudinal axis of the support rail. Owing to the block-typeconfiguration of the base member, the fastening element further lines upinto the electrical components placed on the support rail, so that theelectrical components can be fastened to the support rail directlyadjacent to the fastening elements. “Block-type” in this case means thatthe base member is not only in the form of a thin plate, but has arelatively great volume. Preferably the block-type base member is in theform of a thick disc which is placed on edge in the support rail. Due tothe fact that the fastening element can be fastened to the support railsimultaneously with the electrical components, free spaces now no longerhave to be provided between individual electrical components, so thatthe space available on the support rail can be used more effectively. Atthe same time, the mounting costs and the mounting time can be reduced.The base member of the fastening element is connected directly, forexample via a screw connection or clamping connection, to the supportrail. Additionally, the base member is connected to the support rail viathe connecting element which is guided in the base member. Theconnecting element in this case is guided vertically to the longitudinalaxis of the support rail in the base member. The connecting elementforms a detachable connection to the support rail and the mounting basein that it is guided through the support rail and the mounting base, andmay be for example in the form of a screw, a pin or a bolt. Thefastening element according to the invention may furthermore be furtherformed such that it can also itself transmit electric power orelectrical signals. For this purpose, for example bridge shafts can alsobe formed on the fastening element, via which bridge shafts the electricpower or the signals can be looped through or routed. Further, thefastening element may also assume the function of an end retainer on afree end of the support rail. In this case, the fastening element mayhave a labelling surface by means of which a certain section of thesupport rail which is equipped with electrical components can be marked.Since the fastening element forms a secure connection to the supportrail, the fastening element may also function as the contacting of a PEline between the support rail and the mounting base. As a result, it ispossible for no contact points to be lost at other PE terminals whichare otherwise provided on the support rail. Further, an illuminationmeans, for example an LED bulb or a light guide, may also be arranged inthe fastening element, via which means the support rail can beilluminated directly, which is advantageous in particular in switchgearcabinets which have little illumination.

According to an embodiment of the fastening element, the connectingelement is formed to be self-tapping. “Self-tapping” means in this casethat a lead-through in the form of a bore, through which the connectingelement is guided, does not have to be already provided either on thesupport rail or on the mounting base before the fastening, but that theconnecting element, by a vertical movement downwards towards the supportrail and the mounting base, can drill through the support rail and themounting base and thereby screw into them by cutting edges being formedon the connecting element. For example, the connecting element in thiscase may be formed as a self-drilling screw which is actuated by meansof a tool, in particular a screwdriver, which can be introduced fromabove into the through-hole in the base member. Since this means thatprior machining of the support rail and mounting base by drilling-inopenings is dispensed with and thereby the number of working steps canbe reduced, the entire mounting time can be reduced. In addition, thismeans that the flexibility of the fastening can also be increased, sincethe fastening element can be positioned and fastened at any pointwhatsoever along the support rail and hence along the mounting base.

Further, provision is made for the through-hole to have a shoulderformed as a bearing surface for an upper part of the connecting element.The upper part of the connecting element may for example be a head whichhas a greater diameter than the rest of the connecting element, which ispreferably in the form of an elongate, round shank. Due to the shoulderformed in the through-hole, as a result of which a step is formed in thethrough-hole, the through-hole has two different diameters, with thediameter of the through-hole above the shoulder being greater than thatbeneath the shoulder. Owing to the shoulder which is formed as a bearingsurface, the connecting element can be limited in its vertical movementin that the upper part of the connecting element upon a verticalmovement of the connecting element in the direction of the support railcomes to lie on the shoulder. In addition, this can prevent theconnecting element from being guided too far through the support railand the mounting base and thereby projecting too far from the undersideof the mounting base. Further, the shoulder means that whenscrewing-tight the connecting element which lies with its upper partalready on the shoulder which is formed as a bearing surface, anadditional pressure can be applied in the direction of the mountingbase.

In order to prevent the connecting element from being able to slip outof the through-hole, for example during transport of the fasteningelement prior to mounting on a support rail, a loss prevention elementfor the connecting element is preferably formed in the through-hole. Theloss prevention element is formed above the upper part of the connectingelement in the through-hole, so that, if in addition a shoulder isformed in the through-hole, the upper part of the connecting element isarranged between the loss prevention element and the shoulder and alsois movable only between the loss prevention element and the shoulder.The loss prevention element can be formed by a constriction of thediameter of the through-hole, which can for example be formed by a pin,a shoulder or a bulge.

A further particularly embodiment of the fastening element provides forthe fastening element to have an outer contour which is matched to anouter contour of an electrical component which is to be arranged on thesupport rail. The fastening element thereby forms defined grippingsurfaces by which automated handling is made possible, since for examplegrippers of a robot can grip the support rail together with theelectrical components which are placed thereon by means of the fasteningelements and can move them to the desired position, for example towardsthe mounting base. This means that the handling of a support rail can besubstantially simplified. In addition, a configuration of the fasteningelement which has identical contours to the electrical components caneven out the appearance of a support rail equipped with components. Theouter contour can be formed for example by a housing which surrounds thebase member, so that the housing preferably forms the entire outersurface of the fastening element, the housing preferably being formedfrom an insulating material, such as for example a plastics material. Itis however also possible for the outer contour of the fastening elementto be formed by the base member itself. In addition to the matched outercontour, reference patterns can also be provided on the fasteningelement for optical recognition by means of sensors or cameras on thefastening element.

Another embodiment of the invention provides a method for fastening asupport rail to a mounting base, comprising the following steps:arranging a fastening element on the support rail, arranging a largenumber of electrical components on the support rail, placing the supportrail on the mounting base, and fastening the support rail to themounting base via the fastening element by actuating a connectingelement which is guided in a base member of the fastening element, inthat the connecting element is guided through the support rail and themounting base.

In an embodiment, the invention is distinguished by a method in which,before the support rail is fastened to a mounting base, the support railis first equipped with electrical components and one or more fasteningelements according to the invention. The sequence of the arrangement ofthe electrical components and the fastening elements in such case may beselected in any order whatsoever. The finished equipped support rail canthen be fastened to a mounting base via the connecting element which isguided in the base member of the fastening element, in that theconnecting element is guided through the support rail and the mountingbase. Due to the fact that the fastening element can be fastened to thesupport rail simultaneously with the electrical components, free spacesnow no longer have to be provided between individual electricalcomponents, so that the space available on the support rail can beutilised more effectively. At the same time, the mounting costs and themounting time can be reduced. The base member of the fastening elementis connected directly, for example via a screw connection or clampingconnection, to the support rail. Additionally, the base member isconnected to the support rail and preferably at the same time also tothe mounting base via the connecting element which is guided in the basemember. The connecting element in this case is guided vertically to thelongitudinal axis of the support rail in the base member. The connectingelement forms a detachable connection to the support rail and themounting base, and may for example be in the form of a screw, a pin or abolt.

According to an embodiment of the method, when the connecting element isbeing guided through the support rail and the mounting base, theconnecting element automatically cuts into the support rail and themounting base. For this, the connecting element is preferably formed tobe self-tapping. “Self-tapping” means in this case that a lead-throughin the form of a bore, through which the connecting element is guided,does not have to be provided already either on the support rail or onthe mounting base before the fastening, but that the connecting element,by a vertical movement downwards towards the support rail and themounting base, can drill through the support rail and the mounting baseand thereby screw into the support rail and the mounting base by cuttingedges being formed on the connecting element. For example, theconnecting element in this case may be formed as a self-drilling screwwhich is actuated by means of a tool, in particular a screwdriver, whichcan be introduced from above into the through-hole in the base member.Since this means that prior machining of the support rail and themounting base is dispensed with and thereby the necessary working stepscan be reduced, the entire mounting time can be reduced. In addition,this means that the flexibility of the fastening can also be increased,since the fastening element can be positioned and fastened at any pointwhatsoever along the support rail and hence along the mounting base.Alternatively, it is of course also possible for a bore for guidingthrough the connecting element to be already provided in the supportrail.

There are now a large number of possible ways of configuring anddeveloping the fastening element according to the invention and themethod according to the invention for fastening a support rail to amounting base.

FIG. 1 shows a fastening element 1 for fastening a support rail to amounting base, which element has a block-type, disc-shaped base member 2in which a connecting element 3 is guided. The base member 2 here isformed in two parts, with an upper part 4 and a lower part 5, which areplaced on one another and are interconnected. On the lower part 5 thereis formed a mounting foot 6 via which the base member 2 can be connectedto a support rail by latching or clamping the base member 2 to thesupport rail via the mounting foot 6 in the same manner as theelectrical components are also latched and clamped to the support rail.

The outer contour of the base member 2 here corresponds substantially tothe outer contour of an electrical terminal block which can be placed asan electrical component on a support rail. The fastening element 1 canthus be inserted with an identical shape into a row of electricalcomponents placed on a support rail, as is shown in FIG. 7.

In the base member 2 there is formed a through-hole 7 which extendsacross the upper part 4 and the lower part 5 of the base housing 2 inwhich the connecting element 3 is guided. The through-hole 7 permitsvertical guidance of the connecting element 3 relative to thelongitudinal axis of the support rail on which the fastening element 1is placed from above. For this, a tool can be introduced from above intothe through-hole 7, by means of which tool the connecting element 3 canbe actuated, for example by a rotary movement. The connecting element 3in the embodiment shown here is in the form of a self-drilling screwwhich upon a rotary movement of the connecting element 3 automaticallycuts into and screws itself into a support rail and an underlyingmounting base, as is shown for example in FIG. 3.

FIG. 2 shows a cut-out of the mounting foot 6 of the fastening element 1shown in FIG. 1. The mounting foot 6 shown here has a sheet-metal spring8 in the form of a stirrup, by means of which particularly secureclamping fastening of the fastening element 1 to a support rail can beachieved, so that lateral displacement of the fastening element 1 on thesupport rail can be prevented.

FIG. 3 shows a further possible embodiment of a fastening element 10with a base member 12 which is formed in two parts, with the upper part14 and the lower part 15 of the fastening element 10 beinginterconnected via screws 16 a. The base member 12 is fastened to thesupport rail 20 via clamping blocks 18, which are likewise securelyconnected to the base member 12 via screws 16 b. The upper part 14 andthe lower part 15 of the base member 12 here in each case are in theform of a T-shaped block, so that the entire base member 12 has aplurality of steps, and is thus already matched to the shape of anelectrical terminal block. The clamping blocks 18 are clamped from belowagainst the outwards-bent free ends 21 of the U-shaped support rail 20,and the lower part 15 of the base member 12 lies from above on theoutwards-bent free ends 21 of the U-shaped support rail 20, so that thefree ends 21 of the U-shaped support rail 20 are clamped between aclamping block 18 and the lower part 15 of the base member 12 in eachcase. Around the base member 12 and the clamping blocks 18 there isarranged a housing 19, here shown in a sectional form, which almostcompletely encompasses the base member 12, the screws 16 a, 16 b whichare screwed thereinto and the clamping blocks 18, and thereby in theembodiment shown here forms the outer contour of the fastening element10. In the region of the screws 16 a, 16 b and the through-hole 17formed in the base member 12, openings 22 are provided in the housing19, so that the screws 16 a, 16 b and the connecting element 13 can beactuated with a tool via the openings 22. The connecting element 13, inthe embodiment shown here too, is in the form of a self-drilling screw,it being shown in the embodiment shown in FIG. 3 how the connectingelement 13 is guided through the support rail 20 and a mounting base 40,here in the form of a mounting plate, in order to fasten the supportrail 20 to the mounting base 40.

FIG. 4 is a sectional view through the fastening element 10 shown inFIG. 3. In this case, it can be recognised that the through-hole 17 hasa shoulder 24 which is formed as a bearing surface for an upper part 23,in particular a screw head, of the connecting element 17. The shoulder24 here is formed in the upper part 14 of the base member 12. Due to theshoulder 24 which is formed in the through-hole 17, as a result of whicha step is formed in the through-hole 17, the through-hole 17 has twodifferent diameters, the diameter of the through-hole 17 above theshoulder 24 being greater than that beneath the shoulder 24. Owing tothe shoulder 24 which is formed as a bearing surface, the connectingelement 13 can be limited in its vertical movement downwards towards thesupport rail 20 by the upper part 23 of the connecting element 13 comingto lie on the shoulder 24. A further limitation of the vertical movementupwards of the connecting element 13 which is guided in the through-hole17 is formed by a loss prevention element 25, which in the embodimentshown here is in the form of a bulge formed above the shoulder 24 on theinner wall 26 of the through-hole 17. This means that, in particularduring transport of the fastening element 10, the connecting element 13can be prevented from being able to slip out of the through-hole 17 atthe top. The upper part 23 of the connecting element 13 is thus guidedand movable between the shoulder 24 and the loss prevention element 25.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, such illustration and descriptionare to be considered illustrative or exemplary and not restrictive. Itwill be understood that changes and modifications may be made by thoseof ordinary skill within the scope of the following claims. Inparticular, the present invention covers further embodiments with anycombination of features from different embodiments described above andbelow.

The terms used in the claims should be construed to have the broadestreasonable interpretation consistent with the foregoing description. Forexample, the use of the article “a” or “the” in introducing an elementshould not be interpreted as being exclusive of a plurality of elements.Likewise, the recitation of “or” should be interpreted as beinginclusive, such that the recitation of “A or B” is not exclusive of “Aand B,” unless it is clear from the context or the foregoing descriptionthat only one of A and B is intended. Further, the recitation of “atleast one of A, B and C” should be interpreted as one or more of a groupof elements consisting of A, B and C, and should not be interpreted asrequiring at least one of each of the listed elements A, B and C,regardless of whether A, B and C are related as categories or otherwise.Moreover, the recitation of “A, B and/or C” or “at least one of A, B orC” should be interpreted as including any singular entity from thelisted elements, e.g., A, any subset from the listed elements, e.g., Aand B, or the entire list of elements A, B and C.

LIST OF REFERENCE NUMERALS

-   -   Fastening element 1, 10    -   Base housing 2, 12    -   Connecting element 3, 13    -   Top side 4, 14    -   Underside 5, 15    -   Mounting foot 6    -   Through-hole 7, 17    -   Sheet-metal spring 8    -   Screw 16 a, 16 b    -   Clamping block 18    -   Housing 19    -   Support rail 20    -   Free end 21    -   Opening 22    -   Upper part 23    -   Shoulder 24    -   Loss prevention element 25    -   Inner wall 26    -   Mounting base 40

1-7. (canceled)
 8. A fastening element for fastening a support rail to amounting base, the fastening element comprising: a block-type basemember that is fastenable to the support rail and includes athrough-hole; and a connecting element disposed in the through hole ofthe base member, the connecting element being adapted to fasten thesupport rail to the mounting base, the connecting element beingconfigured to extend through the support rail and the mounting base in afastened state thereof.
 9. The fastening element as recited in claim 8,wherein the connecting element is self-tapping.
 10. The fasteningelement as recited in claim 8, wherein the through-hole has a shoulderincluding a bearing surface for an upper part of the connecting element.11. The fastening element as recited in claim 8, wherein thethrough-hole includes a loss prevention element for the connectingelement.
 12. The fastening element as recited in claim 8, wherein thefastening element has an outer contour which is matched to an outercontour of an electrical component, the electrical component beingdisposed on the support rail.
 13. A method for fastening a support railto a mounting base, the method comprising: disposing the support rail onthe mounting base; arranging a plurality of electrical components on thesupport rail; providing a fastening element including a block-type basemember with a through hole; and guiding a connecting element through thethrough hole, the support rail, and the mounting base so as to fastenthe support rail to the mounting base.
 14. The method as recited inclaim 13, wherein the connecting element automatically cuts into thesupport rail and the mounting base when the connecting element is beingguided through the support rail and the mounting base.